AHS17

A common argument used by opponents of the “Paleolithic” dietary template invokes the ability of humans to change genetically or epigenetically in a short time, such that we are no longer entirely Paleolithic organisms. Recent genetic changes that have occurred since the Agricultural Revolution, such as the increased expression of salivary amylase, are said to illustrate the ability of the human organism to adapt to changing conditions. To assess the validity of this argument, I will explore the processes by which genetic changes occur, and the timescales required for such changes to reach fixation. I will discuss several examples of recent genetic changes that have occurred in the late Paleolithic era and in the post-agricultural era, noting that many of these changes have required particularly strong selection pressures, and are therefore likely to be isolated examples among a pattern of relative genetic homogeneity. I will discuss how epigenetic changes may allow rapid changes to human physiology, in response to specific environmental factors. But I will suggest that most epigenetic changes are unlikely to allow comprehensive adaptation to a new environment.